Re: Apple II slot assignments

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <44.48573139.Logic.IS@logicbbs.org>,  <Jim.Low@logicbbs.org> wrote:
> I have many devices on my Apple IIgs: three hard drives with a total of
> 12 ProDOS partitions, two RAMDisks, two 3.5" floppies, and several
> networked volumes.  I am curious was as to the order they would appear.

[snip]

> Within ProDOS 8, I can't see any logical order the devices appear mapped
> to specific slots,drives.  Not all the devices appear -- only 13 of them
> (14 if you count the 64k RAM mapped to S3,D2).

You don't say which SCSI card you have, but it sounds like you are using
the remapping provided by ProDOS-8, so it doesn't matter in this case.

The rules applied by ProDOS-8 2.0 and later are as follows.

1. /RAM (auxiliary memory 64K ram disk) always appears in S3D2,
   unless a program has currently disabled it.

2. Real devices use drive 1 and 2 of the slot in which they live.

   (a) Your first two IIgs SmartPort devices will appear in S5D1 and
       S5D2.  /RAM5 appears first if it is the boot device, second
       otherwise. 

   (b) If you have the slot 6 "Disk Port" firmware enabled, then S6D1 and
       S6D2 are reserved for 5.25" drives.

   (c) A RAM card will have SnD1 reserved (S6D1 in your case).  The second
       drive will not be used.

   (d) A SCSI card will provide access to the first two partitions via its
       own slot (S2D1 and S2D2 in your case).

3. If there are any devices which support the "SmartPort" firmware
   interface, and have more than two devices available, then ProDOS-8 will
   remap them into unused slot/drive positions.  For the purposes of this
   remapping, only disk I/O devices (5.25" controller or cards with a ProDOS
   driver) are considered.

   All of the remapped devices are handled by a driver provided within the
   language card by ProDOS, which converts the ProDOS driver call into
   a SmartPort call, and routes it to the appropriate slot.

   I'm not sure what rules are followed by the remapping.  In your
   case, it appears that the third device from your disk port (smartport)
   has been remapped as S4D1, and six SCSI partitions would be remapped
   as S1D1, S1D2, S3D1, S4D2, S7D1 and S7D2.

   It appears that the drives are assigned starting with the first unused
   slot/drive number, in ascending slot order, but I don't understand why
   your second 3.5" drive ended up at S4D1.  I would have expected it to
   be S1D1 or S7D2.  It is possible that ProDOS special-cases the slot
   5 SmartPort firmware, or biases the mapping in favour of smaller
   SmartPort chains.

> Of course, not all of my two dozen volumes can be accessed from within
> ProDOS 8.  Is there any way, through software, I can force certain
> volumes to appear in place of some others that appear by default?

Not at present.  The only way to do this is to modify some
undocumented tables which ProDOS sets up in the language card area.  I
have occasionally done this by hand when I've needed to access one of
the higher numbered partitions on my hard drive.

> Or am I looking at physically disconnecting some volumes to access
> others?

Yes, for the moment.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand